How do I know CAC is functioning?

W

walnutcrunch

Well-known member
I was messing around the other day and I was getting a huge amount of CA.

I went to the lens setting menu and there was no indication of anything. Every CAC setting just had the dashes "---". I could go in and see the profile for my lens, and about 3 other lenses, but I couldn't actually see anywhere that the camera understood I had the Canon 17x7.6 2x CAC lens attached and was applying the appropriate CAC.

Is there anyway you can tell it is working?
 
At the top of that menu is something that says " Lens file in use" (or something like that) and next to that you should see your file number listed corresponding to the proper lens attached. When I had my Cac lens, sometimes I would have to reconnect it and go into the Lens menu and shuffle though the Cac files untill the proper one was listed.
 
In the lens setup menu I get
shading select
shading user
cac property
cac card read
cac file delete
cac file init
iris adjust


Everything labelled CAC just has the ---- dashes
If I go into CAC property, I can select yes or dashes

when I select yes I get
Active CAC file No:1
It then has the first file as the kj16ex7.7b irsd ps12 and then i can scroll through a bunch of other different profiles for different lenses.

But if I select anything, absolutely nothing happens.
 
So the kj 16x7.7 isnt your lens? You have the 17x7.6? Or is that a typo?

If you see that there is an CAC active file, and the number corresponds to your lens. You should be all good. Keep in mind that just because CAC is activated, you wont get rid of all of the CA.
 
Sorry it is the 7.7 that's a typo. There is setting 1 that corresponds to my lens, but there are also 4 other settings in that same list that don't.

I was just surprised at the amount of CA, but it was a supremely challenging shot for it I think.

It probably was working, but it's hard to make sure.
 
A lot of the time its easy to mistake lens flare for CA. Lens flare is the blue artifact that shows up usually around highlights (mostly over-exposed highlights). Cac wont fix that.

I had a fujinon XA17x7.6 CAC lens, and there was considerable CA even with the CAC turned on. Maybe we are looking too critically at our image?
 
It wasn't lens flare. I was shooting a huge cedar tree against bright afternoon sky. The tree was a giant purple mess. Especially shooting right in on the boughs.

I was at about nd3 and f8.

But a straight line of a chimney in the same situation had no CA.

So I think it was just very challenging for it. Though I swear I've shot stuff like that before and not had CA
 
I think it's funny that you get all this purple stuff and the image looks bad with the HD lens, yet I get great results out of our $125 SD lenses....hrmmm...
 
walnutcrunch said:
I was at about nd3 and f8.
Click to expand...

Not related to your CA issue. But at f8 your not at optimum sharpness. If you must go to f8 on nd3, use ND4 and try to stay within the 2.8 to 5.6 for sharpest results.

Kit just as an aside, Im using the CAC lens and its proven to be a great lens, without issue for me(apart from breathing - which I consider minor). The bokeh has a nice organic feel which I enjoy a lot. And because Im big on examples, heres a totally out of focus shot, just prior to pulling focus, but you can see what I am talking about.

copcar.jpg
 
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the easy way to see if cac is functioning is to bring up the complete display with the display check button - if CAC is listed on the upper right then it is functioning
 
Thanks for the display check tip.

Just to be clear, the lens has been excellent and very little to no noticeable CA, except for the other day.

I was worried that somehow, in that canon lens control menu, on the lens, I had disabled something or altered how it was talking to the camera.
 
davide said:
Kit,

What lens are you using?

davide
Click to expand...

We have Canon J15x9.5B4 KRS lenses - the originals. We got them for $125 each off of Fleabay. They work great. They do exhibit some minor breathing, which is fine for the price, and they do have external focus, which again, is fine for the price. We will upgrade in the next 6 months or so, but these work great for now. The image looks fantastic.

Just a side note, I had another shooter this past Saturday bring his 500 with the Canon HD 17x7.6 to do one of our cheer competitions (handheld) and I was extremely impressed with the feel of the lens. It was beautiful. The display was very nice too. I loved how fast the zoom could be and how quickly I could pull focus. It was like butter.
 
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